1. Technical Field of the Invention
The present invention relates to an electro-optical device and an electronic apparatus, and more specifically, it relates to the technology suitable for a liquid crystal display device having an active element.
2. Description of the Related Art
Generally, a liquid crystal display panel constituting a liquid crystal display comprises a liquid crystal sealed between two substrates, a plurality of electrodes disposed on inner surfaces of the two substrates facing each other, and optical modulation modes according to the voltage applied between electrodes are realized for each pixel area formed of a pair of electrodes facing each other and the liquid crystal disposed therebetween.
The current mainstream liquid crystal display panels are active matrix liquid crystal display panels that produce the highest screen quality. In this active matrix liquid crystal display panel, a pixel electrode formed on each of the above pixel areas is connected to wires via an active element including a thin film transistor (TFT) and a thin film diode (TFD) having the non-linear current-voltage characteristic.
Some liquid crystal display panels have a semiconductor circuit to supply a predetermined electric potential to a plurality of electrodes in a liquid crystal sealed area formed on a substrate surface portion outside the liquid crystal sealed area that is sealed with a sealing material or the like. This semiconductor circuit is connected to an input terminal formed on a substrate end portion and a wire connected to the electrodes, and outputs a drive electric potential to a plurality of electrodes based on a power source electric potential and a control signal supplied to the input terminal. The semiconductor circuit comprises semiconductor ICs mounted on the surface of the substrates, or comprises a circuit pattern formed directly on the surface of the substrates using thin film deposition technology.
In the above active matrix liquid crystal display, a problem occurs, in that the active element easily causes a dielectric breakdown by the static electricity accumulated in a liquid crystal panel manufacturing process generally due to a low electrostatic withstand voltage of the active element, and thus the active element does not perform its function.
FIG. 8 shows a liquid crystal display panel 100 having a structure to prevent the dielectric breakdown of the above active element. In this liquid crystal display panel 100, an element substrate 110 is bonded to an opposing substrate 120 via a sealing material not shown in the figure, and a liquid crystal is sealed inside the sealing material. A plurality of data lines 111 continuously disposed in a striped manner are formed on the surface of the element substrate 110, and a plurality of pixel electrodes 112 are respectively connected to the data lines 111 via a MIM element not shown in the figure (a diode (two-terminal) element) having a xe2x80x9cmetal-insulator-metalxe2x80x9d structure with a non-linear current-voltage characteristic.
A substrate expansion portion 110a expanding from an outer edge portion of the opposing substrate 120 is disposed on the element substrate 110, the data line 111 is extended onto the surface of the substrate expansion portion 110a, and a connection portion 111 a connected to a semiconductor IC 115 indicated by a one-dot chain line in the figure is disposed on a tip of the data line 111. A plurality of input terminals 113 are formed on the outer edge portion of the substrate expansion portion 110a, and the input terminal 113 is also connected to the semiconductor IC 115.
On the other hand, a plurality of scanning lines 121 disposed parallel to each other and a plurality of opposing electrodes 122 parallel to each other extending in a direction orthogonal to the data lines 111 and connected to these scanning lines 121 are disposed on the opposing substrate 120. The opposing electrode 122 is intersected with the pixel electrode, and the intersected portion forms the pixel area. An area with a plurality of pixel areas P shown in FIG. 9 arrayed in a matrix is referred to as a liquid crystal drive area S. A connection portion 125a disposed on the tip of the scanning line 121 is connected to the semiconductor IC 125 mounted on the substrate expansion portion 120a of the opposing substrate 120. A plurality of input terminals 123 connected to the above semiconductor IC 125 are formed on the outer edge portion of the substrate expansion portion 120a. 
In this liquid crystal display panel 100, a dummy electrode 117 having a U-shape in plan view is disposed on the surface of the element substrate 110. The dummy electrode 117 comprises a pair of dummy electrode units 117a, 117b extending parallel to each data line 111 on both right and left sides of the liquid crystal drive area S, and a dummy electrode unit 117c passing between the connection portion 111a of the data line 111 and the input terminal 113. The dummy electrode 117 is integrally formed so that the dummy electrode portions 117a, 117b, 117c are connected to each other.
In this liquid crystal display panel 100, static electricity accumulated in the manufacturing process is transmitted along the dummy electrode 117 since the dummy electrode 117 is formed, and thus the static electricity is less easily transmitted to the data line 111, and thus the dielectric breakdown of the MIM element can be reduced.
However, although the probability of a dielectric breakdown occurrence of the MIM element is reduced when the above dummy electrode 117 is formed, a pixel defect Q (a white defect attributable to a short circuit defect in a MIM element) can occur along the data line 111 on the dummy electrode unit 117b as shown in FIG. 9. This pixel defect Q occurs in a portion close to the dummy electrode unit 117c when viewed in the extending direction of the data line 111, and occurs in a more extensive range toward the opposite side of the dummy electrode unit 117c closer to the dummy electrode unit 117b. Such a pixel defect Q adversely affects the yield of the product because the defect cannot be discovered until a lighting inspection is carried out after the panel assembly process.
The present invention has been made in light of the above problems and the object of the present invention is to reduce the above pixel defects by providing an electro-optical device with countermeasures for the static electricity.
In order to solve the above problems, an electro-optical device according to the present invention comprises an electro-optical substance disposed between a first substrate and a second substrate, and is characterized in that the first substrate comprises a plurality of first wires extending in a predetermined direction, pixel electrodes connected to the first wires via an active element, an input terminal, and a semiconductor circuit connected to the first wires and the input terminal, the second substrate comprises opposing electrodes disposed facing the pixel electrodes and second wires connected to the opposing electrode at one side in a direction substantially orthogonal to the predetermined direction, an area where the pixel electrodes that face the opposing electrodes via the electro-optical substance is formed into a drive area, and the first substrate further comprises a dummy electrode having a dummy electrode unit extending along the first wires on the side opposite to the second wires in the drive area and a dummy electrode unit passing between the first wires and the input terminal formed continuously to each other.
The dummy electrode is not formed on the second wiring side of the drive area.
A second dummy electrode comprising a dummy electrode unit extending along the first wires on the second wire side of the drive area and a dummy electrode unit passing between the first wires and the input terminal formed continuously thereto is separated from the dummy electrode in the present invention, and the dummy electrode passing between the first wires and the input terminal in the second dummy electrode is preferably formed closer to the input terminal side than the dummy electrode unit passing between the first wires and the input terminal in the dummy electrode.
In the present invention, the second substrate preferably comprises a second input terminal and a second semiconductor circuit connected to the second wires and the second input terminal.
An electronic apparatus according to the present invention comprises the above electro-optical device.
In a conventional liquid crystal display panel shown in FIGS. 8 and 9, when static electricity is accumulated in the second wires, it is assumed that the active element connected to the first wires 111 is subjected to a dielectric breakdown by the charge path in which the discharge occurs from the second wires to the dummy electrode unit 117b facing thereto, a charge moves along the dummy electrode 117, and then the discharge occurs from the dummy electrode unit 117c of the dummy electrode 117 to the connection unit 111a of the first wires, and the above-described pixel defect thus occurs.
On the other hand, in the present invention, the second wires and the dummy electrode are not disposed opposite to each other on a peripheral portion on the second wires side of the drive area, and thus, no movement of charges along the charge path is made, and as a result, the probability of a dielectric breakdown occurrence in the active element is reduced and pixel defects are reduced.
Since the static electricity accumulated in the second wires can be discharged to the second dummy electrode disposed facing thereto by further providing a second dummy electrode in addition to the dummy electrode, the dielectric breakdown attributable to another charge path than the above one, for example, the direct discharge from the opposing electrode to the first wires or the pixel electrode can be reduced. The dummy electrode unit passing between the first wires and the input terminal in the second dummy electrode is disposed closer to the input terminal side than the dummy electrode unit passing between the first wires and the input terminal in the dummy electrode, and thus no discharge can occur between the first wires and the second dummy electrode.